[FIXED] how do I migrate my old magento(2.1.5) database to my new magento2.3.3

Issue

How how do I migrate my old magento(2.1.5) database to my new magento2.3.3 ? my website run environment is : centos 6.9 apache 2.4 php 7.2.24 mysql 5.7.28

my new magento 2.3.3 is a clean project. no data ,no theme,no extension.

Solution

Migrate to Magento 2.1.5 to 2.3.3 (via composer)

You need to know your server requirement for migrating 2.3.3 Server/System Requirement for Magento 2.3.3

Then, the second thing that you need to take the backup of database and your files from the server

Enable Maintenance Mode

php bin/magento maintenance:enable

Installing magento 2.3.3 Version

composer require magento/product-community-edition=2.3.3 --no-update

Update autoload

"autoload": {
"psr-4": {
    "Magento\\Framework\\": "lib/internal/Magento/Framework/",
    "Magento\\Setup\\": "setup/src/Magento/Setup/",
    "Magento\\": "app/code/Magento/",
    "Zend\\Mvc\\Controller\\": "setup/src/Zend/Mvc/Controller/"
},}

You need to add "Zend\Mvc\Controller\": "setup/src/Zend/Mvc/Controller/" this line as mentioned above.

Composer Update for Our Changes

composer update

Clean Cache

php bin/magento cache:clean

Perform Setup and Schema Upgrade

php bin/magento setup:upgrade

Disable Maintenance Mode

php bin/magento maintenance:disable

Checking Magento Version

php bin/magento --version

You can check detail information for migrating and upgrading Magento2 Official Website for Command-Line Upgrade

Answered By - Jaydeep Charadva

Answer Checked By - Clifford M. (PHPFixing Volunteer)